Manufacture of alumina and alkali sulfur salts.



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ADOLF CLEMM, or MANNI-IEIM, GERMANY.

Specification of Letters Patent.

Patented March 26 1907.,

Original application filed April 5,190Eb3crial No. 310,099. Divided andthis application filed January 12,1907. Scrial No. 352,025.

To all ZU/LUTM ff 71m concern.-

Ile it known. that l, Anon? (JLnuM, a subject of the Emperor of Germany,residing at lvlannl'iein'i, Germany, have invented certain new and.useful improvements in Manufacture of .z'ilumina and Alkali CompoundsContaining Sulfur, of which the following is a specification.

This inrentioi'i has for its object to 0011- vert bauxite or otheralui'nini erous material and. alkali sulfate into certain other usefulproducts and it consists in the process substantiatlly as hereinafterset forth for accomplishing this object.

This application is a division ofiny application, Serial No. 310,099,filed April 5, 1906,

wherein I have set forth and claimed a similar process.

In carrying out this process alkali sulfate and carlmn are intimatelymixed with bauxite or similar aluminiferous material in such proportionsof the sulfate and carbcm as are multiples of those theoreticallyrequired to form alkali aluininate. its an example, one hundred. parts,by weight, of bauxite (contaii'iing about sixty-one per cent. Al )3) aremixed with three hundred parts of sulfate of soda and sixty parts ofcarbon; but I do not confine myself to the proportiiims given, thequality of the raw materials employcd may render them more or lessvariable. This mixture is calcined and the calcined mass lixiviated withwater, when an alkali aluminate and an excess of alkali sulfid areobtained in a solution. which is generally of a yellowish or greenishcolor and can be clarilied by allovv'ing'it to stand or by filtration.By treating this solution with sulfureted hydrogen, preferably also withthe applica tion of heat, the alumina of the bauxite used is obtained.as a white precipitate of aluminb um hydroXid and a solution of sodiumsulfohydrate and sodium sulfld remains. The alumina having beenseparated from this solution, the latter maybe used directly for manypurposes in the chemical industry. It can, however, be converted intotliiosulfate by passing through it sulfurous acid, or sodium sulfidmaybe obtained by it in a wellknown manner.

The residue remaining from the above-dc scribed lixiviation of thecalcined mass retains as a rule some alkali and sulfur com pounds, fromwhich further quantities of thiosulfate maybe obtained. This isollectedin the manner described in my original application above referred to bytreating said residue (to which some milk of lune may be added in orderto accelerate the oxidation) with an oxidizing agent-for instance, as byallowing it to eflloresce in the air or by blowing air through saidresi(lue-the mass being thereupon lixiviatcd with water and thiosullateallowed to 'rystallize .out of the liquorthus obtained. after it hasbeen suitably con.-

ccntrated.

I claim 1. In the process of manufacturing alumina the steps whichconsist in mixing aluminiferous material with quantities of alkali,sulfate and carbon which are multiples of those theoretically requiredto form an alkali aluminate and calcining the mixture, lixiviating thecalcined mass and treating the-solution with sulfureted hydrogensubstantially as and for the purpose set forth.

2. In the process of manufacturing alumina, the steps which consist inmixing aluminilerous material with quantities of alkali sulfate andcarbon, which are multiples of those theoretically required to form analkali aluminate, calcining the mixture, lixiviating the calcined muss,treating the solution with sulfur'eted hydrogen, separating thethusobtained precipitate from the remaining so- 5 lution and treatingthe latter with sulfurous acid substantially as and for the purpose setforth. y 3. In the process 01 manufacturing alumina. the steps whichconsist in mixing alu 9 miniferous material with quantities of alkalisulfate and carbon, which are multiples of those theoretical] y requiredto form an alkali aluminatc, calcining the mixture, lixiviating thecalcined mass, treating the solution with,

sull'nreted hydrogen, separating the thusobtained precipitate from theremaining solution' and tree ting the latter with sulfurous acid,treating the insoluble residues of the lixiviated calcined agents,treating the products of oxidation with water conmentrating the solutionthus, obtained, and allowing the-thiosulfate con tained therein to becrystallized out substantially as and for the purpose set forth.

In testimony whereof I allix my signature in presence of two witnesses.

ADOI i oLEMM.

l Wdtnesscs:

mass with oxidizing Ibo

